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Peru Open Ocean Essay

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Peru Open Ocean: Ecosystem Assessment
The south pacific is well known for their upwelling especially around the coast of Peru and it is well known for its high productivity around the world’s oceans and supports a great deal of sea food around the world. However, the region is also known for its fluctuation in the fish stocks due to many biotic and abiotic factors (Figure 1) (Cury, Roy, and Faure 1998; Sandweiss et al. 2004).
El Nino/ Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) have a major impact in the Pacific Basin. Understanding the different climate variability is relevant in order to have better knowledge on the marine living resources that we are dependent on. The equatorial Pacific and the coast of Peru are …show more content…

El Nino is the event that has more effect on this area because it has a significant reduction in nutrients due to warm ocean currents that decreases the level of productivity and abruptly changes the food web. On the other hand, PDO are low frequent oscillation and they have a fifth teen to thirty year cycle (Nathan and Hare 2002; Sandweiss et al. 2004).
The PDO Index is premeditated with spatially average of monthly sea surface temperature that is taken from twenty degrees north form the Pacific Ocean. There are not many hypothesis that may explain the biological responses with any correlating of physical and chemical variation. However, PDO shows fluctuations on productivity, temperature in oceans and air, and fish landings (Nathan and Hare 2002; Sandweiss et al. 2004).
ENSO and PDO seem to have an similar pattern and impact in the region each event seem to target certain species that helps discern them from each other. Throughout the course in history, there are very two distinct regimes: Anchovy and Sardine regime. The anchovy stocks decrease when sardines peak and vice versa. It is how the PDO is distinguish mostly identify by this two distinct fish stocks (Cury, Roy, and Faure 1998; Nathan and Hare 2002; Sandweiss et al.

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